1. Technical Field
The present invention relates to a peelable package capable of keeping its interior airtight when closed and easily opening by being pulled and peeled with a relatively weak force, if required, and to a peelably packaging method. More specifically, the present invention concern a peelable package which can be easily opened by even a person having handicapped fingers. The peelable package can readily open up to a predetermined position in an opening direction with a peeling strength abruptly increased at the predetermined position, and stop opening with assuredness at the predetermined position. Besides, it can be put into practice easily and inexpensively.
2. Background Art
A known example of a package for a tablet or the like is a so-called peelable package which arranges a tablet or the like object to be packed between, for example, two package sheets and adheres predetermined portions of both sheets to each other with heat and under pressure to form a weakly-sealed portion around the object to be packed. This peelable package is provided with a grip flap at an end of each sheet. The sheets are peeled and separated from each other by grasping the grip flaps to open the weakly-sealed portion and take out the packed object.
At least one of the sheets composing the peelable package has an inner surface on which a peelable layer is formed from a resin having little strength so as to be able to peel the respective sheets without damaging them. The grip flap mostly has a length set to a minimum width that finger tips can pick up, for example, about 5 mm, in order to make the medicine package compact.
However, the prior art has the following problems:
(A) It is not easy to open by picking up the grip flaps each set to about 5 mm with finger tips for a patient, e.g., a rheumatoid patient, who experiences difficulty when moving his finger tips delicately and pulling an object with a force put on his finger tips;
(B) The peelable package can easily open by pulling and peeling both sheets with a relatively weak force. However, while an insufficient opening size makes it impossible to take out the packed object, an excessive opening makes the packed object readily jump out of the package. Therefore, it is not easy to open the package up to an adequate position;
(C) The packed object is likely to jump out because the grip flaps of both sheets are unsealed by both hands so as to result in opening the package too much. When the jumped out object is received with hands and picked up by finger tips, it may become unsanitary due to the dirt on finger tips and the like. Further, there is a likelihood that the jumped out object might fall on the floor due to failure to satisfactorily receive it. Therefore, it might be lost or dirtied and damaged.
More specifically, for instance, as shown in FIG. 25, the conventional peelable package forms its rear part as a ]-shaped sealed portion 89 and has a non-sealed area 87 formed so as to extend to a rear end portion of a weakly-sealed portion 83 in the same width. Thus, as shown in FIG. 25(A), before opening the rear part, a tablet 82 is sandwiched between two vertical upright package sheets 81,81, and each sheet 81 has a horizontal bulge 88 in an amount corresponding to the tablet 82. When the package starts opening from this state to a bottom side 90 as shown in FIG. 25(B), both sheets 81,81 are horizontally opened. In other words, both sheets 81,81 let the bulges 88 quickly disappear somewhere between a state shown in FIG. 25(A) and a state shown in FIG. 25(B) to become planar. During the process while these bulges 88 quickly disappear, the tablet 82 on the sheets 81,81 receives reaction therefrom to jump out in many cases. Further, as shown in FIG. 25(B), when it reaches the bottom side 90 of the ]-shaped sealed portion 89, the weakly-sealed portion 83 rapidly increases its area. This results in abruptly stopping the peeling operation at a position of the bottom side 90. At this time, the sheets 81,81 undergo stress to vertically vibrate with ease, thereby causing the tablet 82 to fall down more easily.
Then, for example, as disclosed in Japanese Patent Public Disclosure No. 3-111267, one of the conventional peelable packages increases a sealing width at a midway portion in an opening direction of a weakly-sealed portion to enhance a peeling strength of the thus widened portion so as to stop the opening operation at an appropriate position.
More specifically, as shown in FIG. 26, this peelable package has a peelable layer formed on either surface of at least one of package sheets 81a, which layer is adhered with heat and under pressure to the other package sheet 81b, thereby forming the weakly-sealed portion 83 around the object 82 to be packed. The weakly-sealed portion 83 forms at its midway portion in an opening direction a wide portion 84 where a sealing width of the weakly-sealed portion 83 is increased.
When opening this peelable package 80, both sheets 81a and 81b are peeled and separated from each other by holding grip flaps 85 until they experience an enhanced opening resistance at the wide portion 84 having a peeling strength higher by an amount corresponding to the increase of the sealing width. As a result, the opening operation stops at this wide portion 84. There may be expected an effect of preventing the packed object from jumping out.
However, the conventional technique has increased this sealing width at its midway portion and therefore has the following problems:
(D) The above-mentioned package is directed to a relatively large product such as a test instrument. It is used in a case where the product has a portion disclosed and the disclosed portion is gripped to take the product out thereof Therefore, as for a small and light products such as a tablet, even if a bag portion of the package has a portion opened, it does not assure the capability of taking out all the tablets without failure. Further, it will become difficult for a person having handicapped finger tips to take the tablets out of the bag portion having only a portion opened without dropping the tablets. This results in a need to open a large part of the bag portion or fully open it. Therefore, it is desired to use a technique so as to prevent the tablet or the like from falling out while opening the large part of the bag portion or fully opening it.
(E) In general, the package cannot be made excessively larger than the object to be packed. If made excessively larger, it causes an economical disadvantage. Therefore, the wide portion 84 is limited, at largest, to about twice a width of the portion of the weakly-sealed portion 83 to be opened up thereto. However, the weakly-sealed portion of the peelable package is smoothly going to separate once it starts peeling. Accordingly, even if the peeling strength becomes about as large as twice an initial one at a halfway point, this does not resist the opening so much that it subsequently separates the wide portion to result in being apt to open the package to more than a predetermined length. As a result, even the conventional technique is still likely to let the packed object jump out and fall on the floor inadvertently.
The following is an example of other methods for increasing the peeling strength at a proper position in a direction of opening a weakly-sealed portion.
It is a method of utilizing a peelable package material made through a so-called part coating which forms a peelable layer only on a portion to be opened, and adheres substrate resin directly to the other package material at the other portion. However, this example requires precise positioning of the portion forming the peelable layer and the portion accommodating the object to be packed, which makes it difficult to put it into practice. In addition, many kinds of peelable package materials must be prepared depending on the shape and size of the object to be packed. Thus it has a problem of being troublesome and unable to be put into practice inexpensively.
In view of the above-mentioned problems, the present invention has been created. It has an object to provide a peelable package and a peelably packaging method capable of solving these problems.
Concrete examples of the object are mentioned below.
(a) Providing a peelable package able to be easily opened by even a rheumatoid patient or the like person having handicapped fingers who encounters difficulty in picking up an object by his finger tips, without imposing any particular burden on him;
(b) Inhibiting the packed object from jumping out and falling from the package sheets even if a bag portion is completely opened to the end when opening a peelable package which accommodates a small and light packed object;
(c) Preventing the packed object from jumping out and falling from the package sheets while opening a large part up to a predetermined position of the bag portion when opening the peelable package;
(d) Providing a handy peelable package for storing or carrying a plurality of easily openable and peelable packages all together; and
(e) Providing a peelable package which can easily open up to a predetermined position in an opening direction with a peeling strength abruptly increased at the predetermined position and stop the opening operation at the predetermined position with assuredness, and which can be put into practice readily and inexpensively, as well as a method of producing such a peelable package.
The present invention is a peelable package and a method of producing such a peelable package in the following manner, and it is explained based on, for example, FIGS. 1 to 24 illustrating embodiments of the present invention.
A first aspect has been made by focusing on the fact that it is easier for a rheumatoid patient or the like who experiences difficulty when making a delicate movement of his finger tips, to hold a grip flap between a side surface of his thumb and that of his forefinger (as for a person who cannot move his thumb, between a side surface of his forefinger and that of his middle finger) as shown in FIG. 2 rather than to pick it up with finger tips.
More specifically, the first aspect relates to a peelable package. Sheet-like package materials 2,2 sandwiches an object 7 to be packed therebetween. The package materials 2 are provided with a weakly-sealed portion 4 so as to surround the packed object 7 while leaving a grip flap 3 for each of the package materials 2, thereby forming a bag portion 5 which accommodates the packed object 7 within a non-sealed area 6. The packed object 7 in the bag portion 5 is taken out by grasping and pulling the grip flaps 3 to peel the weakly-sealed portion 4. Assuming that extension lines are drawn from points on a boundary line 21 between the weakly-sealed portion 4 and the grip flap 3, the grip flap 3 is provided with an area 23 where the extension lines are cut by a grip flap outer edge 3a to each have a length of at least 10 mm.
Thus, since the shape of the grip flap is set so as to have a length of at least 10 mm, the grip flap can be held between side surfaces of fingers like the thumb and the forefinger or the forefinger and the middle finger. Therefore, the peelable package can be easily opened by even a rheumatoid patient or the like person having handicapped fingers who experiences difficulty in picking up an object with his finger tips, without imposing any particular burden on himself. However, the area having the length of at least 10 mm is preferably not more than 100 mm.
As mentioned above, if extension lines are drawn from points on a boundary line 21 between the weakly-sealed portion 4 and the grip flap 3, the grip flap 3 is provided with an area 23 where the extension vertical lines are cut by a grip flap outer edge 3a to each have a length of at least 10 mm. If this is explained by relying on, for example, FIG. 8, assuming that vertical lines are drawn from points (P1)-(Pn) on the boundary line 21 between the weakly-sealed portion 4 and the grip flap 3 perpendicularly to the boundary line 21, the grip flap 3 is provided with the area 23 where the extension lines (22i) to (22k) are cut between the points (Pi) to (Pk) and the grip flap outer edge 3a to each have a length (M) of at least 10 mm.
In short, this means that when the patient picks up the grip flap 3 unintentionally so as to open the peelable package by unsealing the weakly-sealed portion 4 as shown in FIG. 2, each grip flap 3 has the area 23 of at least 10 mm length where he can substantially do the movement shown in FIG. 2. As shown in FIG. 1, in the event that the weakly-sealed portion 4 has a front tip 9a on the grip flap side, the extension line may be imagined with the front tip 9a slightly rounded.
A second aspect relates to another peelable package. Sheet-like package materials 2,2 sandwich an object 7 to be packed therebetween. The package materials 2 are provided with a weakly-sealed portion 4 so as to surround the packed object 7 while leaving a grip flap 3 for each of the package materials 2,2, thereby forming a bag portion 5 which accommodates the packed object 7 within a non-sealed area 6. The object 7 packed in the bag portion 5 can be taken out by grasping and pulling the grip flap 3 to peel the weakly-sealed portion 4. The weakly-sealed portion 4 is formed so that a non-sealed area 6 gradually narrows in a direction toward a rear part of the bag portion 5.
Thus the weakly-sealed portion is constructed so that the non-sealed area gradually narrows in the direction toward the rear part of the bag portion. As a rear part of the weakly-sealed portion is going to be unsealed, the packed object moves within a decreasing range in the bag portion to inhibit the movement of the packed object on the package material, accompanying the opening operation. This can prevent the packed object from falling or the like. Consequently, even if the bag portion is completely opened at the end, the packed object can be prevented from moving, which leads to the possibility of solving the problem that the packed object readily falls as it was caused by the conventional technique.
Besides, as mentioned above, the weakly-sealed portion is formed so that the non-sealed area gradually narrows in the direction of the rear part of the bag portion. This provides an advantage of being able to inhibit the vibration of the package material to thereby prevent the jumping-out of the packed object even if the bag portion is fully opened.
More specifically, for example, as shown in FIG. 5(A), before opening the rear part, each of the package sheets 2,2 has a horizontal bulge 29 because the tablet 7 is packed therebetween, as in the conventional construction. But the non-sealed area 6 gradually narrows in the direction toward a front part of a rear inverted V-shape sealed portion 11. Thus, as the weakly-sealed portion 4 is peeled, the non-sealed area 6 where the packed object can freely move in the bag portion 5 gradually narrows. Therefore, as shown from FIGS. 5(A) to 5(B), during the process of peeling the weakly-sealed portion 4 until it reaches a bottom point 30 of the rear inverted V-shape, the bulge 29 of each sheet 2 progressively disappears to result in seldom causing a phenomenon such as the tablet 7 jumping out of the sheets 2 upon receipt of reaction therefrom. In consequence, it is possible to inhibit the jumping-out of the packed object even if the weakly-sealed portion 4 is opened to the rearmost end because the weakly-sealed portion 4 is constructed so that the non-sealed area 6 gradually narrows in the direction toward the rear part of the bag portion 5. The advantage of the second invention can be well understood as a reality if the peelable package made as shown in FIG. 5 and the conventional one made as shown in FIG. 25 are actually opened.
To construct the weakly-sealed portion so that the non-sealed area gradually narrows in the direction toward the rear part of the bag portion as set forth in the second aspect includes forming the rear part of the bag portion in the shapes of letters xe2x80x98Vxe2x80x99, xe2x80x98Uxe2x80x99, a semicircle or the like. To shape the non-sealed area so that it gradually narrows may also include narrowing it step by step like a staircase. But it is more preferable to narrow it smoothly and continuously like the shapes of letters xe2x80x98Vxe2x80x99, xe2x80x98Uxe2x80x99, or a semicircle rather than to narrow it step by step.
The non-sealed area may be gradually narrowed by arranging the rear part of the weakly-sealed portion 4 with two sides 26,26 inclined with respect to an opening direction 24 of the bag portion 5, for example, as shown in FIG. 8. Further, it is preferable to construct the rear part of the weakly-sealed portion 4 so that a center line 31 of the bag portion 5, is made coincident with the opening direction 24 of the bag portion 5, and the rear part is rendered symmetrical with respect to the center line 31 of the bag portion 5 in a left and right direction. This is because the rear part of the weakly-sealed portion 4 is peeled in the same state on both the left and right sides when peeling the weakly-sealed portion 4 due to the symmetrical construction in the left and right direction, thereby stabilizing the sheet surfaces. The foregoing shapes of letters xe2x80x98Vxe2x80x99, xe2x80x98Uxe2x80x99 or a semicircle are all symmetrical in the left and right direction.
Moreover, in the second invention, if the weakly-sealed portion 4 is constructed so as to progressively increase its area in a direction toward its rear part, for example, as shown in FIG. 5, it gradually increases its area until it reaches the bottom point 30 as the package is going to be opened. Thus a gradually increasing force is required in order to continue the unsealing operation, which naturally reduces an unsealing speed. This assures a slow movement of the sheets 2 when the weakly-sealed portion 4 finishes opening to thereby decrease a likelihood of the tablet 7 falling out.
The second aspect does not exclude such a construction that the weakly-sealed portion 4 does not increase its area at the rear part of the bag portion 5, for example, as shown in FIG. 12.
In the first or the second aspect, it is possible to set the peeling strength behind a predetermined position of the bag portion 5 larger than that of the weakly-sealed portion 4 in front of the predetermined position. Due to this arrangement, in the event that the weakly-sealed portion is peeled with a force of a predetermined largeness, the opening operation can be stopped at the position where the peeling strength becomes larger. Accordingly, the packed object can be taken out in a state where the bag partion is opened up to a preferable position.
Particularly, as for the second invention, in the case where the peeling strength behind the predetermined position is set larger than that of the weakly-sealed portion in front of the predetermined position, for example, as shown in FIG. 4, a cavity 13 narrowing forwardly is formed during the unsealing operation of the weakly-sealed portion since the non-sealed area gradually narrows forwardly. Therefore, if the peeling strength is arranged to become large at a predetermined position where such a preferable cavity is formed, it is possible to stop the opening operation once at that position. At that stop position, the existence of the cavity restricts the movement of the packed object over the package materials to further inhibit the falling-down of the packed object from the package materials and the like.
A third aspect relates to still another peelable package. Sheet-like package materials 2,2 sandwich a plurality of objects 7 to be packed therebetween. The package materials 2,2 are provided with weakly-sealed portions 4 so as to surround the respective packed objects 7 while leaving an area which comes to a grip flap 3 for each of the package materials 2, thereby forming a plurality of bag portions 5. The package, materials 2 are each provided with cut lines 17 so as to be able to individually cut and separate peelable packages 1 each provided with a bag portion 5 and a grip flap 3 for the bag portion 5. There is provided a sealed portion 18, which prevents the grip flap 3 from peeling, along the cut line 17 within the grip flap 3 of each peelable package 1. When a peelable package 1 is cut and separated along the cut line 17, assuming extension lines 22 are drawn from points on a boundary line 21 between the weakly-sealed portion 4 and the grip flap 3 of the peelable package 1, the grip flap 3 is provided with an area 23 where the extension lines 22 are cut by a grip flap outer edge 3a to each have a length of at least 10 mm.
The third aspect produces an advantage of improving a handiness because the plurality of peelable packages can be held all together at once. Further, being provided with the anti-peeling sealed portion, it can inhibit the weakly-sealed portion from being unsealed by the movement of the grip flap. Further, the anti-peeling sealed portion is arranged to be formed along the cut line. This can inhibit movement of the package materials to thereby facilitate the formation of the cut lines during production.
On taking the packed objects out of the peelable packages, the independent peelable packages are cut and separated along the cut lines, and then the anti-peeling sealed portions are unsealed by picking up the grip flaps. Thereafter, the weakly-sealed portions are pulled and peeled to open the bag portions and take out the packed objects. At this time, since each grip flap has an area of at least 10 mm length, even a person with handicapped fingers can easily open the peelable packages without imposing any particular burden on himself.
Before providing patients with peelable packages, for instance, the hospital staff may cut and separate the independent peelable packages along the cut lines and unseal the anti-peeling sealed portions by picking up the grip flaps, or the patients themselves may do so.
A fourth aspect relates to still another peelable package. A peelable layer 37 is formed on either surface of at least one of the package materials 2a. The peelable layer 37 is adhered with head and under pressure to the other package material 2b, thereby forming a weakly-sealed portion 4 around an object 7 to be packed. At least one portion of a further extension area from a mid portion in an opening direction of the weakly-sealed portion 4 is provided with a resin lump 39 by fluidizing with heat, part of resin constituting the package material 2a and collecting the fluidized resin. The resin lump 39 has an adhesion strength enhanced more than that of the weakly-sealed portion 4.
According to the fourth aspect, the weakly-sealed portion is formed by adhering the peelable layer formed on one surface of a substrate resin layer with heat and under pressure to the other package material. The thus formed weakly-sealed portion surely seals the surroundings of the packed object. But its adhesion strength is weak enough for the weakly-sealed portion to be readily opened by pulling and peeling it while grasping the grip flaps and the like provided at the ends. When an opening position reaches the resin lump, which has a larger adhesion strength than the weakly-sealed portion, an opening resistance suddenly increases at this position, so that it can be clearly recognized where to stop opening. Thus, the opening operation can be assuredly stopped at this predetermined position.
As a result, while the package of the present invention can be readily opened as far as the packed object is taken out, it is not excessively opened to result in the possibility of removing the likelihood that the packed object inadvertently jumps out of the package, falls on the floor or the like.
Further, this fourth aspect can employ a peelable package material which has a peelable layer formed over entirety of one of its surfaces. This dispenses with a need for precisely positioning a portion for accommodating the packed object with respect to the peelable package material, and another need for preparing many sorts of package materials for the objects to be packed, which have various shapes and sizes. This can put the fourth aspect into practice easily and inexpensively.
The peelable layer 37 is, in general, formed on either surface of a substrate resin layer 36 of the package material 2a. In this case, the peelable layer 37 is disturbed at the resin lump 39 due to fluidization caused by heat, and the substrate resin at the resin lump 39 is directly adhered to the other package material 2b through the thus disturbed portion of the peelable layer 37. This can enhance the adhesion strength of the resin lump 39 and set its strength adhering with the other package material far larger than that of the weakly-sealed portion by properly choosing the kind of substrate resin.
In the case where the peelable layer 37 comprises a first resin 37a forming a continuous phase and second resin particles 37bdispersed in the first resin, the fluidization caused by heat within the resin lump 39 deforms the second resin particles 37bdispersed in the first resin 37a to result in the possibility of increasing the adhesion strength of the resin lump 39. More specifically, the second resin particles dispersed in the first resin are ordinarily flat in a direction of the peelable layer, so that a surface of each second resin particle, namely an area of an interface between each second resin particle and the first resin, is large and an interspacing between the second resin particles is narrow. In consequence, the weakly-sealed portion formed by adhering the peelable layer with heat and under pressure readily starts peeling from the interface between the first resin and each second resin particle upon receipt of an external force and, ultimately, the first resin of the continuous phase coagulates and breaks. Then it is peeled off by a relatively weak force.
On the other hand, at the resin lump, when the resin is fluidized with heat, the second resin particles dispersed in the first resin tend to deform into more stable spheres. This decreases the area of the interface between each second resin particle and the first resin and increases the interspacing between the second resin particles. As a result, this resin lump has a larger adhesion strength than the weakly-sealed portion.
It is preferable to elongate the resin lump 39 of the fourth aspect in a direction substantially perpendicular to the opening direction of the weakly-sealed portion. This can increase the adhesion width of the substrate resin at the resin lump with respect to the opening direction. Therefore, the opening resistance at this position can be increased more apparently, which leads to the possibility of surely stopping the opening operation.
The fifth aspect relates to still another peelable package. Either surface of at least one of the package materials 2a is provided with a peelable layer 37, which is adhered with heat and under pressure to the other package material 2b to form a weakly-sealed portion 4 around an object 7 to be packed. The peelable layer 37 comprises a first resin 37aforming a continuous phase and second resin particles 37b dispersed in the first resin 37a. At least one portion of a further extension area from a mid portion in an opening direction of the weakly-sealed portion 4 is heated to deform the second resin particles 37b dispersed in the first resin 37a. The heated portion 48 has an adhesion strength larger than a front end side portion in the opening direction of the weakly-sealed portion 4.
The fifth aspect forms the weakly-sealed portion by adhering the peelable layer provided on either surface of the substrate resin layer with heat and under pressure to the other package material as well as the fourth aspect. The thus formed weakly sealing portion surely seals the surroundings of the packed object, but its adhesion force is weak. Therefore, it is easily opened by pulling and peeling while grasping the grip flaps provided at the ends. When the opening position reaches the heated portion where the second resin particles dispersed in the first resin deform to decrease the area of interface between the first resin and each of them and to increase the interspacing therebetween with the result of enhancing the adhesion strength to more than that of the other weakly-sealed portion, namely the front end side portion in the opening direction, the opening resistance abruptly increases at this position so as to be able to clearly recognize the position to stop the opening.
As a result, also in this fifth aspect, while the package is easily opened so far as the packed object is taken out, it is not excessively opened. This results in the possibility of removing the likelihood that the packed object inadvertently jumps out, falls on the floor or the like. Further, it is possible to employ a peelable package material having one of its surfaces provided with the peelable layer over its entirety. This dispenses with a need for precisely positioning the portion for accommodating the packed object with respect to this peelable package material and another need for preparing many sorts of package materials for the objects to be packed, which are different in shape and size. Therefore, it can be put into practice readily and inexpensively.
In the fifth aspect, although at least one portion of the further extension area from the mid portion in the opening direction may be heated after the weakly-sealed portion has been formed, a predetermined portion of the peelable layer may be preheated before it is adhered with heat and under pressure to the other package material. In this case, the peelable layer is heated while being opened before it is adhered under pressure to the other package material. Therefore, the second resin particles of dispersed phase readily deform and are fluidized and are adhered to the other package material with their interspacings increased in the further extension area from the mid portion in the opening direction. This can surely increase the adhesion strength of this portion.
The sixth aspect relates to a peelably packaging method. An object 7 to be packed is arranged between a peelable package material 2a provided with a peelable layer 37 on one of its surfaces and the other package material 2b. Both package materials 2a,2b overlaid one on another are guided between and passed through a pair of sealing means 40,40. They are adhered with heat and under pressure to each other with a gap 41 between the pair of sealing means 40,40 narrowed around the packed object 7, thereby forming a weakly-sealed portion 4 around the packed object 7. Further, there is formed a gap 42 wider than the narrow gap 41 at a position adjacent to the gap 41 between the sealing means 40,40 which forms the weakly-sealed portion 4 and at least partly of a further extension area from a mid portion in an opening direction of the weakly-sealed portion 4. The constituent resin of the package material 2a fluidized by the heat and pressure adhesion flows into this wide gap 42 to form a resin lump 39 at this position.
The foregoing resin lump is formed by fluidizing the substrate resin and the resin of the peelable layer which constitute the package material. The fluidization of the constituent resin differs depending on the kind of resin, heating temperature of the sealing means, pressure, gap between the sealing means, passing speed (pressurizing time) or the like sealing conditions. Accordingly, it is possible to form the resin lump at a predetermined position by sophisticatedly setting these sealing conditions. However, depending on the kind of resin, heating temperature, pressure, passing speed or the like, it is not easy to form the weakly-sealed portion and the resin lump by one heat and pressure adhesion operation during the process of continuously producing the packages.
On the other hand, the sixth aspect forms the wide gap at the position adjacent to the narrow gap between the sealing means and at least part of the further extension area from the mid portion in the opening direction of the weakly-sealed portion. Flowed into this wide gap is the constituent resin of the package material fluidized by the heat and pressure adhesion to thereby form the resin lump at this portion. This can easily form the weakly-sealed portion and the resin lump at predetermined positions through one heat and pressure adhesion operation by employing sealing means set to provide a gap therebetween depending on the shape of the product. In other words, the sixth aspect can easily form the resin lump at a predetermined position by using sealing means set to have a gap therebetween depending on the shape of the product. Therefore, even in the case of continuous processing, it can efficiently pack the object.
The resin lump can be formed by several applications of a heat and pressure adhesion operation, like an example case where another heat and pressure adhesion operation is applied to a predetermined portion of the further extension area from the mid portion in the opening direction after the weakly-sealed portion has been formed.
The sixth aspect generally adopts a pair of rolls, bars or the like for the sealing means. In order to adhere both package materials to each other with heat and under pressure through these means, normally the gap therebetween has to be at least smaller than the total thickness of both package materials. However, in many cases each sealing means has a surface provided with concave portions and convex portions like undulations of a file, which are engaged with one another. As for the sealing means of this type, the gap generally means a spacing between the trough of the concave portion and the peak of the convex portion Even if the spacing between the peak and the trough is larger than the total thickness of both package materials, both package materials can be adhered together under pressure through these sealing means by reducing a spacing between peaks of mutually engaged concave and convex portions in comparison with the total thickness of both package materials.
In the fourth to sixth aspects, the package materials forming the package are sufficient if at least one of them is a peelable sheet-like package material and therefore are not limited to those formed by laminating two sheet-like package materials one on another such as the conventional one. For example, they may be formed by hermetically sealing a peripheral edge of an opening of a cup-like container with a package sheet, or may take other package forms.
The package materials are satisfactory if at least one of them has either of its surfaces provided with a peelable layer. Therefore, the other package material is not limited to synthetic resin but may be an aluminum foil or the like metal material having one of its surfaces provided with a resin layer. Further, the other package material may have one of its surfaces provided with a peelable layer as well as the one package material.
As for the substrate resin of the constituent resin of the package material, thermoplastic synthetic resin such as, for example, polypropylene is employed. Thus it is a material which attains a high adhesion strength through heat adhesion to the other package material. On the other hand, the peelable layer is a material which readily causes a coagulant break, interface break, interlayer break or the like by a relatively weak force, although it adheres with heat to the other package material. Concrete examples are a resin material comprising polypropylene resin of a continuous phase, and polyethylene resin dispersed in this polypropylene resin, and the like.
Although the peelable layer may be formed only at a required portion of the package material, it is also possible to employ a peelable package material provided with the peelable layer over an entirety of one of its surfaces since it increases adhesion strength at predetermined portions by forming a resin lump in the further extension area from the mid portion in the opening direction or by heating the further extension area. This case is preferable since it need not precisely position the portion for accommodating the packed object with respect to the peelable package material and besides can attend to the packed objects of various shapes and sizes with one or a few kinds of package materials.